Question #N687
The graph of the equation $y = \frac{1}{2}(x+1)(x-3)$ intersects the x-axis at two points. What are the x-coordinates of these two points?
A. -1 and 3
B. 1 and -3
C. 2 and -2
D. -2 and 4
Correct Answer is: A
The graph of the equation intersects the x-axis when y = 0. Setting the equation equal to zero gives $0 = \frac{1}{2}(x+1)(x-3)$. This equation is satisfied when either x+1=0 or x-3=0. Solving for x in each of these equations yields x = -1 and x = 3. Therefore, the x-coordinates of the two points of intersection are -1 and 3.